We are exploring the mechanisms by which antimicrobial agents damage biologic membranes; the target sites of action; and the nature of selective toxicity. The antimicrobials of interest to us are amphotericin B, nystatin and their water soluble derivatives. Several membranes including fungi, red blood cells and model membranes of various compositions are under investigation. Our goals are to improve therapy for systemic fungal infections and to understand better factors responsible for the diversity of biologic membranes. BIBLIOGRAPHIC REFERENCES: Sud, I.J., Feingold, D.S.: Detection of agents that alter the bacterial cell surface. Antimicrob. Ag. Chemother. 8:34-37, l975. Sud, I.J., Feingold, D.S.: Phospholipids and fatty acids of Neisseria gonorrhoeae. J. Bacteriol. 124:713-717, l975.